In recent years natural and artificial soluble polymers have been bound to haptens (Inman 1975, Siciliano et al, 1985) or to proteins (Abramenko et al, 1983) or prepared as copolymers with oligosaccharides (Kochetkov et al, 1982), to create interesting T-independent antigens and T cell stimulating molecules (Inman, 1975; Siciliano et al, 1985; McKluskey et al, 1988) immunotoxins (Printseva et al, 1985) and immunodrugs (Rihova et al, 1986). Proteins non-covalently linked to artificial polycations have also been reported to behave as T-independent antigens (Vinogradov, 1982). Carbodiimide (CDI) has been used to link proteins to each other, or to polymers (Petrov et al, 1979; Abramenko et al, 1983).